Yeah, I mean that Ramune is such an everyday thing in Japan that, when you ask a Japanese perosn to think of a carbonated drink, Ramune is most likely the first thing that comes to mind. Ramune is that pale blue shade, and they're usually served in blue glass bottles.
By the way, do you know of additional color schemes not used in Splatfests I don't have there besides the red-and-purple Transformers theme that apparently rarely comes up in Squad Battles?